During this past summer, Moss Motors in California introduced a wood rimmed
steering wheel for the Miata. This long awaited aftermarket option utilizes the factory
airbag and is a direct replacement for the leather wrapped wheel that is standard
equipment on many Miatas.

I first saw one of these wheels at the Miata '96 International Convention in
Toronto. The Moss Motors wheel appears to be well made and is offered at a reasonable
price, $250. However, I was not overwhelmed by its appearance. The standard black airbag
in the center of the wheel seemed out of place next to the wood rim. This detracted from
the look l hoped to achieve.

It was at this point that I began to investigate other options. Nardi and Momo
both offer a selection of wood rimmed steering wheels in a variety of designs and
diameters. I immediately found exactly what I wanted in Momo's "Grand Prix"
offering. This 13.8" diameter wheel (slightly smaller than the Mazda factory wheel
diameter of 14.2") is made of Italian Zebrano wood with thick brushed aluminum spokes
at the three, six, and nine o'clock positions. The spokes have two rows of five holes each
drilled for appearance. The horn button with the "Momo" logo is located in the
center of the wheel (as it should be). Craftsmanship of the Momo wheel was flawless and
the wood finish was not unlike a fine piece of furniture.

NOTE!Be advised, the Nardi and Momo style of aftermarket steering wheels require
removal of the standard driver-side airbag, should your car be so equipped. Although it
may be legal for the auto owner to do this, we caution you to think long and hard before
you remove the airbag. The authors of this article and the M Club do not advocate removal
of your airbag. In anticipation of this modification, Drake has removed the factory
slotted seat belt buckles and retrofitted new ones with a "gripper" bar inside.
This type of buckle allows the lap portion of the belt to be cinched tightly at all times.
Only the upper torso portion of the shoulder belt needs to be locked by the inertia reel.
Thus there will be very little movement of the upper body towards the steering wheel if
the car comes to a sudden stop.

Now that I knew the wheel I wanted, the next step was to determine the adapter
hub that would fit the Momo wheel to the Miata. Since all U.S. Miatas come equipped with
airbags (and it is currently still illegal for a dealer to disconnect the airbag), a Momo
adapter kit for the Miata is not marketed in the States. Although most aftermarket vendors
admitted there was an available adapter that would fit the Miata, all indicated they could
not legally do the job. Also, none of the vendors would divulge which adapter kit was
suitable for the Miata. A call to friend Andy Cork at Brain-Storm Products in Atlanta,
however, revealed the answer: the adapter hub for the Mazda 323 would fit the Miata with
minor modifications. A non-airbagged Miata will require the same adaptor.

Even after some heavy hinting to my long-suffering wife, Connie, it still was a
surprise to find a Momo "Grand Prix" steering wheel and #5702 adapter hub under
the tree on Christmas morning !

Now came the tricky part -- installation. I knew I was over my head so I
contacted good friend/Miata guru Drake Daum who agreed to help with the conversion. Both
Drake and I researched the project through service manuals and the Internet. On a cold,
snowy Sunday afternoon in mid-January 1997 we tested the waters.

Before starting the installation, be sure to park the car with the front wheels
straight and the steering wheel centered.

The first step is to disable the airbag. First, disconnect the negative battery
lead (10mm nut). Next disconnect the clockspring connectors located below the steering
column. These connectors are accessible by removing two Phillips head screws holding the
access plate in place. The blue and orange clockspring connectors are interlocked.
Disconnect the smaller orange connection before unplugging the blue connector. Drake and I
found that it is almost impossible to disconnect the clockspring connectors unless you
first pull back a black rubber boot that encases the rear portion of the plugs. This step
is critical because the clockspring connectors isolate the airbag module from its back-up
power source.

With the airbag disabled, it may now be disengaged from the steering wheel. Just
remove the four 10mm attachment nuts, which are accessible at the back of the steering
wheel. Disconnect two more connectors behind the airbag module (orange single-lead horn
connector and a blue twin-lead airbag connector). Remove the airbag module and store it in
a safe place.

Be extremely careful when handling the airbag module. Be sure to always carry
the module with the face (trim) side pointing away from you. According to one of the ace
mechanics at the Fairborn City Garage, the disconnected airbag module can be deployed by
static electricity or the voltage from a standard AA battery ! Never use an ohmmeter to
test the airbag leads for continuity. The voltage from the test leads may be enough to
discharge the airbag.

Removal of the stock steering wheel is next. First, remove the steering wheel
nut from the steering shaft using a 21mm socket and 6" extension. Have your helper
hold the steering wheel in place while you break the nut free. Next, remove the steering
wheel by utilizing a standard steering wheel puller. Trust us -- you WILL need a puller.
(I borrowed one from a friend. You can buy one at Sears for about 20 dollars.) Attach the
puller to the wheel with three metric bolts (8.0 x 1.25 x 25) by screwing them into
existing holes in the steering wheel. Depending on the thickness of the puller used, it
may be necessary to use some spacer washers on the metric bolts because the threaded holes
are very shallow. The puller must be snugged down against the steering wheel structure
before attempting to actually remove the wheel. Slowly begin turning the puller center
shaft in a clockwise direction. The steering wheel will separate from the steering shaft
with a bang, so don't be surprised ! The wheel will only move a fraction of an inch as the
puller unseats it from the taper on the steering shaft. Carefully thread the blue and
orange connectors out through the rectangular access hole in the steering wheel and remove
the wheel.

With the steering wheel removed, you will now be looking at a yellow label on
the clockspring cover and the electric pigtail encased in a plastic fixture located near
the six o'clock position. This pigtail is the cable that terminates in the blue/orange
connectors to the airbag and horn. Do not turn the clockspring assembly more than a few
degrees from this position.

Now come the "minor modifications" needed to make the Momo #5702 hub
fit your Miata. First, cut off the cable ty-wrap securing the pigtail to the clockspring
strain relief. Then completely cut off the plastic strain relief from the riveted
clockspring connector assembly. Using a Dremel cutting wheel or sharp X-acto knife, trim
the outer edges of the riveted plastic connector to minimize its cross-sectional shape.
Now cut off the stock blue/orange electrical connectors from the short pigtail as close to
the connectors as possible. Be sure to note the green wire attached to the orange
connector for the horn. Slide off the black cable sheath, shorten the sheath by about
1", and slide it back on the three wires. (Remember? One for the horn, two for the
airbag.) Install a short length of shrink tubing over the sheath and slide it down over
the reshaped plastic clockspring connector. Carefully heat the tubing to shrink it for a
secure fit over the forward end of the sheath and the trimmed plastic connector. This
sheath is necessary to avoid chafing the wires as they pass through the hub adapter.

Remove the brass contact ring assembly from the back of the adapter hub. It is
seated in rubber and merely pops right off. This ring and its attached wire are not used
in the Miata application. Locate the TOP of the adapter. Note the two small holes on the
back side at the 6 and 12 o'clock positions. Centered below the 6 o'clock hole, and flush
with the small lip immediately below the hole, draw a small rectangle. We machined out a
relief area about 5/16" deep, about 5/16" high, and about 7/16" wide. This
area is adjacent to a small hole already drilled through the hub by Momo. This existing
hole is not used in the Miata application. The relief cut was started on a drill press and
finished by hand with a Dremel tool. The hub material is relatively soft and easy to
machine. Once the relief area is properly sized, we drilled a 3/8" pass-through hole
in the top center of the relief area. Be very careful when drilling this hole. The hole
exit is very close to one of the four hub support spokes on the front side. We also found
it necessary to elongate this 3/8" hole with our Dremel tool. We further reshaped
this hole into an ellipse coinciding with the long dimension of the relief cut
(east-west). This relief cut and oval hole are necessary to accommodate the trimmed
clockspring connector assembly which is riveted to the face of the clockspring connector
cover plate surrounding the steering shaft.

Thread the electrical pigtail (without any end connectors) through the new
pass-through hole in the adapter hub. Gently seat the hub adapter on the splines of the
steering shaft, making sure the two points on the turn signal canceling sleeve (white
nylon) engage the two holes in the back of the hub at the 12 and 6 o'clock positions. The
trimmed clockspring connector should fit into the machined relief slot in the back of the
hub. Check to be sure the hub turns freely on the steering shaft. Make sure the hub
portion marked "Top" is in the 12 o'clock position. Finger-tighten the steering
wheel nut on the shaft and attach the steering wheel and horn collar to the hub using the
six Allen head screws supplied. Check that the steering column is not locked. If it is,
when unlocked, the steering wheel may very well be off-center.

Before tightening the steering wheel nut to the specified torque, reconnect the
battery and take a test drive around the block to make sure the steering wheel is
straight. If not, return to the garage, remove the wheel, nut, and adjust as needed. Take
another drive to confirm steering wheel placement before torquing the steering wheel nut
to 29 - 36 lb.-ft.

Detach the steering wheel from the adapter hub. Thread the 3-wire pigtail
through the access hole in one of the Momo hub support struts. Secure the electrical
pigtail to the hub using a nylon ty-wrap. Next install the accordion-shaped, cosmetic
rubber hub collar. Be sure to place the reference/index marks on the hub and collar at the
12 o'clock position. Now re-attach the horn collar and steering wheel and tighten screws.

Peel back a portion of the electrical pigtail threaded through the hub. The
green wire is for the horn. The other two wires are for the now-absent airbag. Fasten
these two wires together using a splice connector and stuff them back into the hub adapter
cavity. Fasten a female spade connector to the green wire and attach to the male blade
connector on the back of the horn assembly. Now center the horn button and gently press
into place.

Personally, of all the aftermarket modifications I've made to my Miata, I think
I enjoy this one the most. It completely changes the interior of the car and makes the
steering a little quicker, probably due to the smaller diameter wheel. The only drawback
I've experienced thus far is a slight obscuring of the upper portions of some of the
gauges (tach and speedo), again, due to the smaller diameter of the wheel.

Dave

Editor's note: We received this tip from Doug Thomas, but we haven't actually tried
it. Doug used an RX-7 adapter instead of the Momo #5702.

The installation revolved around using an adapter for an '88 RX7. I pried off the
brass ring and drilled and elongated one hole and connected it to the factory connectors.
No cutting or splicing!!! Perfect location from the stalks!!!

Editor's note: We received this tip from Paul Chan. Paul had trouble with the Momo
#5702 on his Canadian Non-Airbag Miata.

Got the multimeter out and tested everything from wires to relays. It seems the problem
with my horn was due to poor tolerances with the Momo Hub Adaptor #5702.

The brass ring that makes contact with the clockspring can have intermittent contact -
you can check this by verifying that there is 12V at the clockspring and at the Momo wire
to the positive terminal of the Momo horn button. It seems the inner plastic of the hub
adaptor was not trimmed properly and the plastic would touch the clockspring instead of
the brass portion of the ring. The Miata clockspring is VERY close to the center of the
brass ring - you can tell by the wear marks.

This problem was intermittent because the plastic was fine on other portions of the
ring thus only showing up depending on the position of the wheel! Once I trimmed the inner
plastic all was fine!

That's one to keep in the back of your mind if you know of anyone having horn problems
with a Non-Airbag (i.e. Canadian) Miata!